Process for the preparation of ethylene copolymers

ABSTRACT

Process for the preparation of ethylene copolymers comprising the copolymerization of ethylene with olefins CH 2 ═CHR, in which R is a hydrocarbyl radical with 1-12 carbon atoms carried out in the presence of a catalyst comprising (i) a solid catalyst component comprising Mg, Ti, halogen and specific 1,3-diethers of formula (I)  
                 
 
in which R is a C 1 -C 10  hydrocarbon group, R 1  is methyl or ethyl, optionally containing a heteroatom, and R 2  is a C4-C12 linear alkyl optionally containing a heteroatom, and (ii) an organo-Al compound. The obtained copolymers are endowed with good comonomer distribution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending application Ser. No.10/503,104, which is a national phase filing under 35 U.S.C. §371 ofInternational Application PCT/EP03/05787, filed May 30, 2003, claimingpriority to European Patent Application 02077339.6 filed Jun. 13, 2002;the disclosures of application Ser. No. 10/503,104, InternationalApplication PCT/EP03/05787, and European Patent Application 02077339.6,each as filed, are incorporated herein by reference.

The present invention relates to the process for the preparation ofethylene copolymers, to the catalyst components used for suchpreparation and to specific elastomeric ethylene copolymers.

Ethylene copolymers represent a very broad family of products having aprominent importance in the polyolefin field.

One of the most important groups of ethylene copolymers is constitutedby the Linear low-density polyethylene (LLDPE). Due to itscharacteristics, it finds application in many sectors and in particularin the field of wrapping and packaging of goods where, for example, theuse of stretchable films based on LLDPE constitutes an application ofsignificant commercial importance. LLDPE is commercially produced withliquid phase processes (solution or slurry) or via the gas-phaseprocesses. Both processes involve the widespread use of Ziegler-NattaMgCl₂-supported catalysts that are generally formed by the reaction of asolid catalyst component, in which a titanium compound is supported on amagnesium halide, with an alkylaluminium compound. In order to beadvantageously usable in the preparation of LLDPE, said catalysts arerequired to show high comonomer incorporation properties and goodcomonomer distribution suitably coupled with high yields. The abovecharacteristics in fact would ensure the preparation of a product havingthe desired density and, at the same time, a low content of hydrocarbonsoluble fractions.

Another important group of ethylene copolymers is represented by theelastomeric ethylene copolymers such as ethylene/propylene (EPM)elastomers optionally containing smaller proportions of dienes (EPDM).The said elastomers are produced industrially by solution processes orslurry processes carried out, for example, in the presence of certainZiegler-Natta catalysts based on vanadium compounds such as vanadiumacetylacetonate. These catalysts in fact, in view of their goodcapability to randomly distribute the comonomers, are able to produce asofter and more elastomeric product with respect to the catalysts basedon titanium compounds. Their basic downside however, is the fact thatthey are not able to produce predominantly isotactic crystallinepolypropylene and therefore they cannot be used in the production ofin-situ heterophasic copolymers such as polypropylene impact copolymersconstituted by crystalline polypropylene matrix within which anelastomeric rubbery phase is dispersed. On the other hand, the titaniumbased catalysts generally do not have a good capability to distributethe comonomer and therefore the quality of the rubbery phase is notparticularly high especially when EPR/EPDM polymers with an amount ofethylene in the range of 40-70% by weight (having a satisfactorybehavior during vulcanization) are to be produced. In these conditionsin fact, the fraction of crystalline ethylene copolymers produced wouldbe so high to deteriorate the properties of the rubber. The availabilityof this kind of product would be of high importance because theelastomeric copolymers obtained by titanium based catalysts, generallyshow a better homogeneity with the crystalline matrix.

We have now surprisingly found a process capable to produce ethylenecopolymers endowed with good comonomer distribution comprising thecopolymerization of ethylene with olefins CH₂═CHR, in which R is ahydrocarbyl radical with 1-12 carbon atoms carried out in the presenceof a catalyst comprising the product obtained by contacting (i) a solidcatalyst component comprising Mg, Ti, halogen and the 1,3-diethers offormula (I)

in which R is a C₁-C₁₀ hydrocarbon group, R₁ is methyl or ethyl,optionally containing a heteroatom, and R₂ is a C4-C12 linear alkylgroup optionally containing a heteroatom, with (ii) an organo-Alcompound.

Preferably, R is a C1-C5 alkyl group, R₁ is methyl and R2 is a C7-C10linear alkyl group.

Examples of representative 1,3 diethers that are included in the aboveformula (I) are: 2-methyl-2-pentyl-1,3-dimethoxypropane,2-methyl-2-n-hexyl-1,3-dimethoxypropane,2-n-heptyl-2-methyl-1,3-dimethoxypropane,2-n-octyl-2-methyl-1,3-dimethoxypropane,2-n-decyl-2-methyl-1,3-dimethoxypropane,2-ethyl-2-butyl-1,3-dimethoxypropane,2-ethyl-2-pentyl-1,3-dimethoxypropane,2-ethyl-2-n-hexyl-1,3-dimethoxypropane,2-n-heptyl-2-ethyl-1,3-dimethoxypropane,2-n-octyl-2-ethyl-1,3-dimethoxypropane,2-n-decyl-2-ethyl-1,3-dimethoxypropane. The use of2-n-octyl-2-methyl-1,3-dimethoxypropane is particularly preferred.

Particularly preferred are the solid catalyst components comprising atitanium compound, containing at least one Ti-halogen bond, and aninternal electron-donor compound chosen from the above mentioned1,3-diethers, supported on magnesium halide.

In a particular embodiment, the Mg-halide is in active form. The activeform of the magnesium halides present in the catalyst components of theinvention is recognizable by the fact that in the X-ray spectrum of thecatalyst component the major intensity reflection which appears in thespectrum of the non-activated magnesium halides (having surface areasmaller than 3 m²/g) is no longer present, but in its place there is ahalo with the position of the maximum intensity shifted with respect tothe position of the major intensity reflection, or by the fact that themajor intensity reflection presents a half-peak breadth at least 30%greater that the one of the corresponding reflection of thenon-activated Mg halide. The most active forms are those in which thehalo appears in the X-ray spectrum of the solid catalyst component.

Among the magnesium halides, the chloride is the preferred compound. Inthe case of the most active forms of the magnesium chloride, the haloappears in place of the reflection which in the spectrum of thenon-activated magnesium chloride is situated at the interplanar distanceof 2.56 Å.

Preferred titanium compounds are the halides or the compounds of formulaTiX_(n)(OR⁴)_(4-n), where 0≦n≦3, X is halogen, preferably chlorine, andR⁴ is a C₁-C₁₀ hydrocarbon group. The titanium tetrachloride is thepreferred compound. Satisfactory results can also be obtained with thetrihalides, particularly TiCl₃ HR, TiCl₃ ARA, and with the halogenalcoholates such as TiCl₃ OR, where R is a C₁-C₁₀ hydrocarbon radical.

The 1,3-diethers of the present invention can be prepared according tothe methods disclosed in the European patent application No. 0361493.Said diethers, used in the preparation of Ziegler-Natta catalysts, aregenerally synthesized by the reaction of alkylating agents with thediols corresponding to the above diethers. A way of synthesis of saiddiols consists in the reduction of the corresponding malonates.

The preparation of the solid catalyst components can be carried outusing various methods.

For example, the magnesium halide (preferably used in a form containingless than 1% of water), the titanium compound and the electron-donorcompound are milled together under conditions that cause the activationof the magnesium halide; the milled product is then caused to react oneor more times with TiCl₄ in excess, optionally in the presence of anelectron-donor, at a temperature ranging from 80 to 135° C., and thenrepeatedly washed with a hydrocarbon (such as hexane) until no chlorineions can be detected in the wash liquid.

According to another method, the anhydrous magnesium halide ispreactivated according to known methods and then reacted with an excessof TiCl₄ containing the electron-donor compound and optionally analiphatic, cycloaliphatic, aromatic or chlorinated hydrocarbon solvent(for example hexane, heptane, cyclohexane, toluene, ethylbenzene,chlorobenzene, dichloroethane). In this case also the operation takesplace at a temperature between 800 and 135° C. The reaction with TiCl₄,in the presence or absence of an electron-donor, is optionally repeatedand the solid is then washed with hexane to eliminate the non-reactedTiCl₄.

According to a preferred method, a MgCl₂.nROH adduct (particularly inthe form of spheroidal particles) where n is generally from 1 to 6, andROH is an alcohol, preferably ethanol, is caused to react with an excessof TiCl₄ containing the electron-donor compound and optionally one ofthe above mentioned hydrocarbon solvents. The reaction temperatureinitially is from 0° to 25° C., and is then increased to 80-135° C.Then, the solid is reacted once more with TiCl₄, in the presence orabsence of the electron-donor, separated and washed with a hydrocarbonuntil no chlorine ions can be detected in the wash liquid.

These MgCl₂.nROH adduct can be prepared in spherical form from meltedadducts, by emulsifying the adducts in a liquid hydrocarbon andthereafter causing them to solidify by fast quenching. A typical methodfor preparing these spherulized adducts is reported in U.S. Pat. No.4,399,054, the description of which is herein incorporated by reference.In a preferred method, the thus obtained spherulized adducts can besubjected to thermal dealcoholation at a temperature ranging from 50 and150° C. until the alcohol content is reduced to values lower than 2 andpreferably comprised between 1.5 and 0.3 mols per mol of magnesiumdihalide, and are finally treated with chemical reagents capable ofreacting with the OH groups of the alcohol and of further dealcoholatingthe adduct until the content is reduced to values which are generallylower than 0.5 mols.

The treatment with the dealcoholating chemical agents is carried out byusing an amount of such an agent which is large enough to react with theOH groups present in the alcohol contained in the adduct. Preferably,the treatment is carried out using a slight excess of said agent, whichis then removed prior to the reaction of the titanium compound with thethus obtained support.

In the case in which a total or partial reduction of the valence stateof the titanium compound is desired, the chemical dealcoholation of theMgCl₂.pROH adduct can be carried out by using agents having a reducingactivity, for instance an Al-alkyl compound such as Al-triethyl,

According to yet another method, magnesium alcoholates andchloroalcoholates (the chloroalcoholates can be prepared particularly asdescribed in U.S. Pat. No.4,220,554) are caused to react with TiCl₄ inexcess containing the electron-donor compound, operating under thereaction conditions already described.

According to a further method, complexes of magnesium halides withtitanium alcoholates (the MgCl₂.2Ti(OC₄H₉)₄ complex is a typicalexample) are caused to react, in a hydrocarbon solution, with TiCl₄ inexcess containing the electron-donor compound; the separated solidproduct is reacted again with an excess of TiCl₄, in the presence orabsence of electron-donor, and then separated and washed with hexane.The reaction with TiCl₄ is carried out at a temperature ranging from 80°to 130° C.

According to a variance of the latter method, the MgCl₂ and titaniumalcoholate complex is caused to react in a hydrocarbon solution withpolyhydrosiloxane; the separated solid product is reacted at 50° C. withsilicon tetrachloride containing the electron-donor compound; the solidis then reacted with TiCl₄ in excess, in the presence or absence ofelectron-donor, operating at 80°-130° C.

Independently from the specific preparation method, after the lastreaction with TiCl₄ in the presence of the electron-donor, it ispreferable to separate the solid obtained (by way of filtration, forexample), and cause it to react with an excess of TiCl₄ at temperaturesranging from 80° to 135° C., before washing it with the hydrocarbonsolvent.

Finally, it is possible to cause to react TiCl₄ in excess and containingthe electron-donor with porous resins such as partially cross-linkedstyrene-divinylbenzene in spherical particle form, or porous inorganicoxides such as silica and alumina, impregnated with solutions ofmagnesium compounds or complexes soluble in organic solvents.

The porous resins which can be used are described in the European patentapplication No. 0344755.

The MgCl₂/electron-donor molar ratio used in the reactions indicatedabove generally ranges from 2:1 to 30:1, preferably from 4:1 to 12:1.

The electron-donor compound is fixed on the magnesium halide in aquantity generally ranging from 1 to 25% molar with respect to MgCl₂.

In particular, the 1,3-diethers of formula (I) are present on thecatalyst component in a quantity generally ranging from 5 to 30% weight,preferably from 8 to 25% weight.

In the solid catalyst components the Mg/Ti molar ratio is generally from30:1 to 3:1; in the components supported on resins or on inorganicoxides the ratio can be different and usually ranges from 20:1 to 2:1.

As explained above, the said catalyst are able to produce ethylenecopolymers characterized by a good comonomer distribution. Inparticular, in the preparation of both linear low density ethylenecopolymers and elastomeric ethylene copolymers it have been obtainedvery good quality products by using catalyst components containing1,3-diethers of formula 1 in which R is a C₁-C₁₀ alkyl group, R₁ ismethyl or ethyl, optionally containing a heteroatom, and R₂ is a C4-C12linear alkyl group optionally containing a heteroatom with the provisothat when R₁′ is ethyl R₂ is higher than C4.

With these catalysts components and particularly in the cases in whichR′ is methyl and more particularly with the use of2-methy-2-octyl-1,3-dimethoxypropane as internal donor, have beenobtained elastomeric ethylene copolymers containing from 35 to70%/weight of ethylene, from 30 to 65% weight of an olefin CH₂═CHR, inwhich R a hydrocarbyl radical with 1-12 carbon atoms, and from 0 to 10%of a polyene characterized by (i) a Molecular Weight Distributionexpressed by Mw/Mn of higher than 3, (ii) a content of 2-1regioinvertions of the α-olefin units of lower than 5% and (iii) a valueof the Shore A measured according to ASTM D2240 and content by weight ofethylenic units, calculated on the basis of the whole polymer, such thatthe point defined by such values falls below the curve defined by thefollowing equation:Y=0.0438X ²−4.1332X+Awhere Y is the value of the Shore A measured according to ASTM D2240, Xis the weight percentage of ethylene units in the polymer calculated byNMR and A is 153. Preferably A is 145 and more preferably 137.

Preferably, the content of 2-1 regioinvertions is lower than 1% and itis also preferred that the Mw/Mn ratio is higher than 4 and morepreferably higher than 4.5.

The complex of the above characteristics is the result of the optimalcomonomer distribution.

In fact, as an additional result the said elastomeric copolymers arealso characterized by a low content of insoluble fraction which isgenerally lower than 15% and in particular lower than 10%.

As already noted, the elastomeric copolymers used in the presentinvention are also characterized by a low crystallinity. Preferably, thecrystallinity, expressed as the enthalpy of fusion determined by DSCanalysis, is lower than 10 J/g, more preferably lower than 5.

The said elastomeric copolymers moreover have an intrinsic viscosity [η]ranging from 1 to 6 dl/g, more preferably from 2 to 5dl/g.

In the elastomeric copolymers of the invention the α-olefin CH₂═CHR ispreferably selected among those in which R is an alkyl having from 1 to3 carbon atoms and in particular propylene. When polyene units arepresent their amount preferably ranges from 0.1 to 20% by weight,preferably from 1 to 10%. The content by weight of units derived fromethylene is preferably between 35 and 70%, more preferably between 40and 60%. The content by weight of units derived from the α-olefin ispreferably between 30 and 65%, more preferably between 40 and 60%.

Polyenes which can be used in the process of the present inventioninclude:

(a) polyenes capable of giving unsaturated units, such as:

unconjugated linear dienes such as trans-1,4-hexadiene,cis-1,4-hexadiene, 6-methyl-1,5-heptadiene, 3,7-dimethyl-1,6-octadiene,11 -methyl-1,0-dodecadiene, 5,6-dimethyl-1,6-octadiene,7-methyl-1,6-octadiene;

monocyclic diolefins such as, for example, cis-1,5-cyclooctadiene and5-methyl-1,5-cyclooctadiene;

bicyclic diolefins such as, for example, 4,5,8,9-tetrahydroindene and 6-and/or 7-methyl-4,5,8,9-tetrahydroindene;

alkenyl or alkylidene norbornenes such as, for example,5-ethylidene-2-norbornene, 5-isopropylidene-2-norbornene,exo-5-isopropenyl-2-norbornene and 5-vinyl-2-norbornene;

polycyclic diolefins such as, for example, dicyclopentadiene,tricyclo[6.2.1.0^(2,7)]_4,9-undecadiene and the 4-methyl derivativethereof;

FE 6024 (US)

(b) unconjugated diolefins capable of cyclopolymerization, such as1,5-hexadiene, 1,6-hepta-diene and 2-methyl-1,5-hexadiene;

(c) conjugated dienes such as, for example, butadiene and isoprene.

As explained above the said elastomers can be used as such or they canbe blended with predominantly crystalline propylene polymers in thepreparation of heterophasic polymer compositions.

The polymeric compositions of the invention may be prepared by mixingthe components in the melted state, for example in a single or twinscrew extruder. The components of the mixture may be fed directly intothe extruder or may be premixed in the solid state. However, it ispreferred to prepare such composition via the reactor blending techniquecomprising two or more sequential polymerization step.

A further subject of the present invention is therefore a polyolefincomposition, comprising:

(A) 5 to 95 parts by weight of a crystalline propylene polymer having anisotacticity index greater than 80, selected from polypropylenehomopolymer and propylene copolymers containing 0.5 to 15 mol % ofethylene and/or an α-olefin having 4 to 10 carbon atoms, and

(B) from 5 to 95 parts by weight of the elastomeric copolymers definedabove.

Preferably, the amount of (A) is from 10 to 90 and more preferably from30 to 70 while for the component (B) preferably the amount is from 10 to90 and more preferably from 30 to 70.

The propylene polymer constituting component (A) preferably has anisotactic index, determined by means of measuring the solubility inxylene, greater than 85, more preferably greater than 90.

As mentioned before in the component (B) the α-olefin CH₂═CHR ispreferably selected among those in which R is an alkyl having from 1 to4 carbon atoms and in particular propylene. When polyene units arepresent their amount preferably ranges from 0.1 to 20% by weight,preferably from 1 to 10%. The content by weight of units derived fromethylene is preferably between 35 and 70%, more preferably between 40and 60%. The content by weight of units derived from the α-olefin ispreferably between 30 and 65%, more preferably between 40 and 60%.

As shown by the lower values of Shore A the heterophasic compositions ofthe invention are, for the same average content of ethylene, moreflexible than the compositions of the prior art and this represent animportant advantage in this application field.

The elastomers and the compositions which are the object of the presentinvention can be subjected to vulcanization or crosslinking in order toproduce thermoplastic elastomeric compositions for use in theapplication sectors cited above.

The terms vulcanization and crosslinking comprise both the actualcrosslinking or vulcanization of the elastomer and the reaction by meansof which the grafting of the more or less crosslinked elastomer on thecrystalline polypropylene phase can take place as a result of thereaction promoted by the crosslinking system used.

Among the various vulcanization techniques known in the art, thepreferred technique is dynamic vulcanization. When working according tothis technique, the compositions of the invention are subjected tokneading or to other shear forces in the presence of crosslinking agentsand, if appropriate, coadjuvants thereof, at temperatures between 140and 240° C., preferably at temperatures higher than the melting point ofthe crystalline phase. The compositions of the invention can beimpregnated with an oil extender for regulating their hardness, eitherbefore the addition of the crosslinking agent or at the start or end ofvulcanization. The oil extender used can be of various types, forexample aromatic, naphthenic or preferably paraffinic. It is used inquantities such that weight ratios between the oil extender andcomponent B of between 1:5 and 5:1, preferably between 1:2 and 2:1, areobtained.

The crosslinking agents which can be used are those commonly known inthe art, such as organic peroxides, preferably having a half-life of theorder of 10-200 seconds in the temperature range in which crosslinkingnormally takes place, and non-peroxidic agents such as the derivativesof 1,2-diphenylmethane, 1,2-diphenylethane and benzopinacol. Aparticularly suitable group of non-peroxidic agents consists of thefurane derivatives described in EP361205, among which difurfuralaldazineand 1,5-difurfuryl-1,4-pentadien-3-one can also be used.

As coadjuvant compounds for the crosslinking, liquid 1,2-polybutadieneor compounds of the triallyl cyanurate type can be used.

The elastomers of the present inventions when subject to crosslinkingdisplay valuable properties. In particular, the combination of goodelastic properties, as evidenced by low values of compression andtension set, and high value tensile strength break makes them suitableproducts for all the conventional applications of these polymers. Inaddition, the high capability that they have in the incorporation ofextending oils makes it possible to lower the Shore of the formulationsuntil to the desired value without suffering from blooming problems.

Before they are subjected to dynamic vulcanization, the compositions ofthe invention can be provided with various additives, such as heatstabilizers, antioxidants, mineral fillers or any other type of agentscustomarily used in the art.

A further subject of the invention is therefore vulcanized thermoplasticcompositions obtained by the vulcanization processes described above, asmanufactured, as well as moulded articles obtainable from the saidcompositions.

The polymerization process of the invention for producing ethylenecopolymers can be carried out either continuously or discontinuously.Said polymerization process can be carried out according to knowntechniques for example slurry polymerization using as diluent an inerthydrocarbon solvent, or bulk polymerization using the liquid monomer(for example propylene) as a reaction medium. Moreover, it is possiblecarrying out the polymerization process in gas-phase operating in one ormore fluidized or mechanically agitated bed reactors.

The polymerization is generally carried out at temperatures ranging from20 to 120° C., preferably from 40 to 80° C. Hydrogen or other compoundscapable to act as chain transfer agents can be used to control themolecular weight of the polymer.

The catalyst component of the invention can be in the above processes assuch or, alternatively, it can be pre-polymerized before being used inthe main polymerization process. This is particularly preferred when themain polymerization process is carried out in the gas phase. Theprepolymerization can be carried out with any of the olefins CH₂═CHR,where R is H or a C1-C10 hydrocarbon group. In particular, it isespecially preferred to pre-polymerize ethylene or mixtures thereof withone or more α-olefins, said mixtures containing up to 20% in moles ofα-olefin, forming amounts of polymer from about 0.1 g per gram of solidcomponent up to about 1000 g per gram of solid catalyst component. Thepre-polymerization step can be carried out at temperatures from −10° C.to 80° C., preferably from 5 to 50° C., in the liquid or gas phase. Theco-catalyst can be the same as, or different from, the cocatalyst usedin the main polymerization process. The pre-polymerization step can beperformed in-line as a part of a continuous polymerization process orseparately in a batch process. The batch pre-polymerization of thecatalyst of the invention with ethylene in order to produce an amount ofpolymer ranging from 0.5 to 20 g per gram of catalyst component isparticularly preferred. The prepolymerized catalyst component can alsobe subject to a further treatment with a titanium compound before beingused in the main polymerization step. In this case the use of TiCl₄ isparticularly preferred. The reaction with the Ti compound can be carriedout by suspending the prepolymerized catalyst component in the liquid Ticompound optionally in mixture with a liquid diluent; the mixture isheated to 60-120° C. and kept at this temperature for 0.5-2 hours.

Examples of gas-phase processes wherein it is possible to use thecatalysts of the invention are described in WO 92/21706, U.S. Pat. No.5,733,987 and WO 93/03078. These processes comprise a pre-contact stepof the catalyst components, a pre-polymerization step and a gas phasepolymerization step in one or more reactors in a series of fluidized ormechanically stirred bed.

In the preparation of the elastomeric ethylene copolymers of theinvention and of the deriving heterophasic compositions specificembodiments can be performed.

Preferably the heterophasic compositions of the invention are preparedby sequential polymerisation operating in at least two reactors inseries in which, whatever the order and using the same catalyst of theinvention in the various reactors, in one of the reactors the(co)polymer (A) is synthesised and in the other reactor the copolymer(B) is synthesised. The polymerization can conveniently be carried outin the gas phase using a fluidised bed reactor.

Preferably in the first reactor the (co)polymer (A) is synthesised bypolymerizing propylene optionally in the mixture with minor amounts ofethylene and/or n α-olefin CH₂═CHR, where R is an alkyl radical havingfrom 2 to 10 carbon atoms, in the presence of the catalyst of theinvention. In a subsequent reactor, a mixture of ethylene and at leastone α-olefin CH₂═CHR¹, where R¹ is an alkyl radical having 1 to 10carbon atoms and optionally a diene, is polymerised to obtain thecopolymer B described above.

When an elastomeric ethylene copolymer containing diene units is to beproduced the polymerization can be suitably be carried out by (a)impregnating with at a least a portion of the diene the prepolimerizedcatalyst of the invention, or (b) in case an heterophasic composition isto be produced, by impregnating with the diene the crystalline portion(A) of the heterophasic composition, before carrying out thecopolymerization of ethylene, alpha-olefin and diene. By adopting thistechnique a higher polymerization activity and a better dieneincorporation in the polymer will be obtained.

The following examples are given by way of non-limiting illustration ofthe invention.

Characterizations

Comonomer Content

The content of 1-butene in the ethylene-butene copolymers was determinedvia Infrared Spectrometry.

The proportions of propylene in the ethylene/propylene copolymers weredetermined by ¹³C NMR analysis carried out using a Bruker AC200 machine,at a temperature of 120° C., on samples prepared by dissolving about 300mg of polymer in 2.5 cc of a 3:1 trichloro-benzene/C₂D₂Cl₄ mixture. Thespectra were recorded with the following parameters:

-   5 Relaxation delay =12 sec,-   Number of scans =2000 -2500.-   The intrinsic viscosity [η] was measured in tetraline at 135° C.-   The Differential Scanning Calorimetry (DSC)

Calorimetric measurements were performed by using a differentialscanning calorimeter DSC Mettler. The instrument is calibrated withindium and tin standards. The weighted sample (5-10 mg), obtained fromthe Melt Index determination, was sealed into aluminum pans, heated to200° C. and kept at that temperature for a time long enough (5 minutes)to allow a complete melting of all the crystallites. Successively, aftercooling at 20° C./min to −20° C., the peak temperature was assumed ascrystallisation temperature (Tc). After standing 5 minutes at 0° C., thesample was heated to 200° C. at a rate of 20° C./min. In this secondheating run, the peak temperature was assumed as melting temperature(Tm) and the area as the global melting hentalpy (ΔH).

The molecular weight distribution was determined by GC carried out on aWaters 150 machine in ortho-dichlorobenzene at 135° C.

Melt Index:

Melt index (M.I.) are measured at 190° C. following ASTM D-1238 over aload of:

2.16 Kg, MI E=MI_(2.16).

21.6 Kg, MI F=MI_(21.6).

The ratio: F/E=MI F/MI E=MI_(21.6)/MI_(2.16) is then defined as meltflow ratio (MFR)

Density:

Density was determined on the homogenised polymers (from the Melt Indexdetermination) by using a gradient column and following the ASTM D-1505procedure.

Xylene Solubility (XSRT):

The solubility in xylene at 25° C. was determined according to thefollowing modalities: about 2.5 g of polymer and 250 ml of o-xylene wereplaced in a round-bottomed flask provided with cooler, reflux condenserand kept under nitrogen. The obtained mixture was heated to 135° C. andwas kept under stirring for about 60 minutes. The final solution wasallowed to cool to 25° C., under continuous stirring; it was thenfiltered off and divided in two portions of 100 ml each. The firstsolution was evaporated in a nitrogen flow at 140° C. to reach aconstant weight; the weight of the soluble portion was calculated(XSRT). The latter was treated with 200 ml of acetone and theprecipitated polymer was recovered by filtration and dried at 70° C.under vacuum. From this weight, the amount of polymer insoluble inacetone is calculated (amorphous part).

-   Shore (A) measured according to ASTM D2240-   Determination of the regioinvertions: determined by means of C¹³-NMR    according to the methodology described by J. C. Randall in “Polymer    sequence determination Carbon 13 NMR method”, Academic Press 1977.    The content of regioinvertions is calculated on the basis of the    relative concentration of S_(αβ)+S_(ββ) methylene sequences.-   Compression set 100° C.: ASTM D395, method B-   Tension set 100° C.: ASTM D412, using a sample according to ASTM    1329.-   Tension set 23° C.: ASTM D412, using a sample according to ASTM    1329.-   Elongation at break: ASTM D412, using a microspecimen.-   Tensile strength: ASTM D412-   E100 ASTM D412-   E200 ASTM D412

EXAMPLES Ethylene/1-butene polymerization general procedure

A 4.0 liter stainless-steel autoclave equipped with a magnetic stirrer,temperature, pressure indicator, feeding line for ethylene, propane,1-butene, hydrogen, and a steel vial for the injection of the catalyst,was purified by fluxing pure nitrogen at 70° C. for 60 minutes. It wasthen washed with propane, heated to 75° C. and finally loaded with 800 gof propane, 1-butene (as reported in table 2), ethylene (7.0 bar,partial pressure) and hydrogen (2.0 bar, partial pressure).

In a 100 cm³ three neck glass flask were introduced in the followingorder, 50 cm³ of anhydrous hexane, 9.6 cm³ of 10% by wt/vol, TEAL/hexanesolution, optionally an external donor (E.D., as reported in table 2)and the solid catalyst (in the amount reported in table 2). They weremixed together and stirred at room temperature for 10 minutes and thenintroduced into the reactor through the steel vial by using a nitrogenoverpressure.

Under continuous stirring, the total pressure was maintained constant at75° C. for 120 minutes by feeding ethylene. At the end the reactor wasdepressurised and the temperature was dropped to 30° C. The recoveredpolymer was dried at 70° C. under a nitrogen flow and weighted.

Ethylene/Propylene Polymerization: General Procedure

In a 4.25 litre autoclave fitted with a stirrer, a manometer, atemperature indicator, a system for feeding the catalyst, monomer supplylines and a jacket for thermostatic regulation, previously purged byflushing with ethylene at 80° C., are introduced at room temperature 242g of hexane. The temperature was brought to 50° C. and then 392 g ofpropane and the reported amount of hydrogen are introduced into thereactor. Afterwards, the amounts of ethylene and propylene given inTable 3 were introduced into the reactor. The catalyst component thetriethylaluminum and optionally the external electron donor compoundwere injected under a pressure of ethylene and the polymerization tookplace. During the polymerization a mixture of ethylene/propylene, thecomposition of which is reported in table 3, was fed in order to keepthe pressure constant. After the polymerization time reported in table 3the reaction was stopped, the polymer obtained was isolated by removalof the non-reacted monomers and was then dried under vacuum.

Example 1 Preparation of the solid catalyst component

The spherical support, prepared according to the general methoddescribed in ex. 2 of U.S. Pat. No. 4,399,054 (but operating at 3000 rpminstead of 10000) was subjected to thermal treatment, under nitrogenflow, within the temperature range of 50-150° C., until sphericalparticles having a residual alcohol content of about 35 wt. % (1.1 molof alcohol per mol of MgCl₂) were obtained.

50 g of this support were charged, under stirring at 0° C., to a 1500cm³ reactor containing 1000 cm³ of pure TiCl₄. The temperature wasslowly raised to 40° C. and then 14.2 cm³ of2-methyl-2-octyl-1,3dimethoxypropane, were slowly added, then thetemperature was further raised to 100° C. in 60 minutes and keptconstant for 60 minutes. Stirring was discontinued, settling was allowedto occur and the liquid phase was removed at the temperature of 100° C.Further 1000 cm³ of freshly TiCl₄ were added and the temperature wasraised to 110° C. and kept constant for 30 minutes. After 10 minutessettling the liquid phase was removed at the temperature of 100° C. Athird treatment with TiCl₄ at 110° C. for 30 minutes was performed, and,after settling and siphoning, the residue was washed with anhydrousheptane (500 cm³ at 90° C. then 3 times (500 cm³ each time) withanhydrous hexane at 60° C. and further 4 at room temperature. Thecomponent in spherical form was vacuum dried at 50° C. 41.5 g ofcatalyst was recovered. The catalyst characteristics are reported intable 1. The catalyst was then used in the ethylene/butenepolymerization procedure according to the conditions reported in table 2together with the polymerization results.

Example 2

115 cm³ of dry heptane were charged to a 350 cm³ reactor containing 20 gof the support prepared as described in Example 1 and the temperaturewas lowered and set to −10° C. Under stirring at 10° C., 3.8 cm³ of2-methyl-2octyl-1,3dimethoxypropane and then 172 cm³ of 10% wt/voltriethyl aluminum alkyl in heptane, were slowly added in 60 minutes. Thetemperature was then raised to 20° C. in 90 minutes, kept at 20° C. for60 min. and then raised to 70° C. in 150 min. and kept constant for 60minutes. Stirring was discontinued, settling was allowed to occur andthe liquid phase was removed at the temperature of 70° C. The residuewas washed with anhydrous heptane at 70° C. (once) and at 25° C.(twice). The spherical solid residue was suspended in 300 cm³ of dryheptane and the temperature lowered to 0° C. In 60 minutes were slowlyadded 39 cm³ of Ti Cl₄ diluted with 11 cm³ of heptane. At the end, thetemperature was raised to 80° C. in 45 minutes and kept constant for 180minutes. After 10 minutes settling the liquid phase was removed and theresidue was washed with anhydrous heptane at 80° C. (once) then 3 timeswith anhydrous hexane at 60° C. and further 4 at room temperature. Thecomponent in spherical form was vacuum dried at 50° C. 19.8 g ofcatalyst was recovered. The catalyst characteristics are reported intable 1. The catalyst was then used in the ethylene/butenepolymerization procedure according to the conditions reported in table 2together with the polymerization results.

Examples 3-5

50 g of this support prepared as described in Example 1 were charged,under stirring at 0° C., to a 1500 cm³ reactor containing 1000 cm³ ofpure TiCl₄. The temperature was slowly raised to 40° C. and then 5.2 cm³of 2-ethyl-2-n-butyl-1,3dimethoxypropane, under stirring at 0° C., wereslowly added to a 750 cm³ reactor containing 500 cm³ of pure TiCl₄. Thetemperature was maintained at 0° C. and then 21 g of the above describedsupport, were charged. The temperature was raised to 100° C. in 60minutes and kept constant for 60 minutes. Stirring was discontinued,settling was allowed to occur and the liquid phase was removed at thetemperature of 100° C. Further 500 cm³ of freshly TiCl₄ were added andthe temperature was raised to 120° C. and kept constant for 60 minutes.After 10 minutes settling the liquid phase was removed at thetemperature of 100° C. The residue was washed with anhydrous heptane at90° C. then 3 times with anhydrous hexane at 60° C. and further 4 atroom temperature. The component in spherical form was vacuum dried at50° C. 14.6 g of catalyst was recovered. The catalyst characteristicsare reported in table 1. The catalyst was then used in theethylene/butene polymerization procedure according to the conditionsreported in table 2 together with the polymerization results.

Examples 6-8 Preparation of solid catalyst component

The spherical support, was prepared according to the general methoddescribed in ex. 2 of U.S. Pat. No. 4,399,054 (but operating at 3000 rpminstead of 10000) having a residual alcohol content of about 57.4 wt. %(about 2.7 mol of alcohol per mol of MgCl₂).

14.2 cm³ of 2-methyl-2octyl-1,3dimethoxypropane, under stirring at 0°C., were slowly added to a 750 cm³ reactor containing 250 cm³ of pureTiCl₄. The temperature was maintained at 0° C. and then 11 g of theabove described support, were charged. The temperature was raised to100° C. in 60 minutes and kept constant for 120 minutes. Stirring wasdiscontinued, settling was allowed to occur and the liquid phase wasremoved at the temperature of 100° C. Further 250 cm³ of freshly TiCl₄were added and the temperature was raised to 120° C. and kept constantfor 60 minutes. After 10 minutes settling the liquid phase was removedat the temperature of 100° C. The residue was washed with anhydrousheptane (200 cm³ ) at 90° C. then 5 times (200 cm³ each time) withanhydrous hexane at 60° C. and one further at room temperature. Thecomponent in spherical form was vacuum dried at 50° C. 6.9 g of catalystwas recovered. The catalyst characteristics are reported in table 1.

The polymerization has been carried out according to the generalethylene/propylene polymerization procedure under the conditionsreported in table 3. The characterization of the polymer is reported intable 4.

Comparison Example 1 Preparation of solid catalyst component

The same catalyst preparation disclosed in example 6 was repeated withthe only difference that 9,9′bis-(dimethoxy)-fluorene was used insteadof 2-methyl-2octyl-1,3dimethoxypropane. The polymerization has beencarried out according to the general ethylene/propylene polymerizationprocedure under the conditions reported in table 3. The characterizationof the polymer is reported in table 4.

Example 9

52 g of the support prepared as described in Example 1 were charged,under stirring at 0° C., to a 1500 cm³ reactor containing 1000 cm³ ofpure TiCl₄. The temperature was slowly raised to 40° C. and then 14.7cm³ of 2-methyl-2octyl-1,3dimethoxypropane, were slowly added, then thetemperature was further raised to 100° C. in 60 minutes and keptconstant for 60 minutes. Stirring was discontinued, settling was allowedto occur and the liquid phase was removed at the temperature of 100° C.Further 1000 cm³ of freshly TiCl₄ and 14.7 cm³ of2-methyl-1,3dimethoxypropane,were added and the temperature was raisedto 110° C. and kept constant for 30 minutes. After 10 minutes settlingthe liquid phase was removed at the temperature of 100° C. A thirdtreatment with TiCl₄ at 110° C. for 30 minutes was performed, and, aftersettling and siphoning, the residue was washed with anhydrous heptane(500 cm³ at 70° C. (twice) then 4 times (500 cm³ each time) withanhydrous hexane at 60° C. and further 4 at room temperature. Thecomponent in spherical form was vacuum dried at 50° C. 43.2 g ofcatalyst was recovered. The catalyst characteristics are reported intable 1.

The polymerization has been carried out according to the generalethylene/propylene polymerization procedure under the conditionsreported in table 3. The characterization of the polymer is reported intable 4.

Comparison Examples 2-3 Catalyst component preparation

The same catalyst preparation disclosed in example 9 was repeated withthe only difference that diisobutylphthalate was used instead of2-methyl-2octyl-1,3dimethoxypropane. The polymerization has been carriedout according to the general ethylene/propylene polymerization procedureunder the conditions reported in table 3. The characterization of thepolymer is reported in table 4.

Examples 10-11 Catalyst preparation

The catalyst was prepared as described in Example 2. The catalystcharacteristics are reported in table 1. The polymerization has beencarried out according to the general ethylene/propylene polymerizationprocedure under the conditions reported in table 3. The characterizationof the polymer is reported in table 4.

Example 12 Preparation of an elastomeric heterophasic compositiondirectly in the reactor

32.7 g of a solid catalytic component, prepared according to Example 6,were precontacted in a 50 ml glass flask with 12.3 mg oftriethylaluminium (TEAL) in 5 ml of anhydrous hexane. The mixture wasfed under propylene flow to a 4.25 liters steel autoclave, previouslypurged by successive washings first with hexane for one hour at 80° C.and then with gaseous propylene for one hour at 80° C. 1150 g of liquidpropylene together with 1500 cm³ of hydrogen were then fed at 30° C. Thetemperature was then brought to 60° C. and the polymerization took placefor 20 minutes. After that period propylene was vented and the reactorwent to room temperature. In the same reactor at 30° C., 204 cm³ of H₂34 g of ethylene and 132 g of propylene were fed the temperature wasraised to 60° C. and the polymerization started again. The compositionof the bath was kept constant by feeding a mixture of the two monomerswith 50% by weight of ethylene. Copolymerization was carried out for 95minutes. This gave 669 g of total polymer whose properties are shown inTable 5.

Comparative Example 4

The same polymerization procedure of example 11 was carried out with thedifference that the same catalyst system disclosed in comparativeexample 2 was used. Copolymerization results are shown in Table 5.

Example 13

100 g of the polymer obtained as disclosed in Example 7 were impregnatedwith 30 g of Flexon 876-paraffin oil. This mixture was introduced intoan internal mixer of the Banbury type at a temperature of 180° C., at 60R.I.P. together with 50g of carbon black, 5 g of ZnO, 2.5 g of Triallylcyanurate (TAC) and 6 g of Peroximon F40 and the mixture was mixed for 6minutes for the dynamic crosslinking of the product. 30 g of mixturewere moulded in a plate press for 5 minutes at 200° C. and then cooledin a second press maintained for 10 minutes at 23 ° C. Afterconditioning at room temperature for 48 hours, the plates obtained(120×120×2 mm) were characterized. The results of the characterizationare shown in Table 6.

Comparative Example 5-6

The same crosslinking procedure disclosed in Example 13 was carried outon the product obtained in comparison example 2-3. The results of thecharacterization are shown in Table 6. TABLE 1 Catalyst compositionCatalyst Composition Example Ti^(t) Ti³⁺ Mg Cl I.D. Solv. N wt. % wt. %wt. % wt. % wt. % wt. % 1 2.7 — 18.3 61.4 13.5 2.8 2 and 10 5.2 4.0 15.760.5 12.2 2.3 3-5 3.2 — 13.7 50.5 10.1 3.8 6-8 3.5 — 17.2 60.1 18 1.6 92.6 — 18.5 58.7 15.7 1.0

TABLE 2 Ethylene/Butene copolymerization Melt Index 1-C₄- D.S.C. Polym.Catalyst E.D: Al/E.D. 1-C4- H2 time Polymer Activity E (I.R.) Density TmΔH X.S. Example mg Type m. ratio g bar min g Kg/gcat dg/mi F/E wt. %g/cc ° C. J/g wt. % 1 19.6 2M2O-DMP 14 150 2.0 120 190 9.7 0.16 32.4 6.20.9160 125.0 120.4 13.6 2 21.8 — — 200 2.0 120 325 14.9 0.81 28.1 7.10.9189 125.1 136.1 12.4 3 20.7 — — 100 2.0 120 330 15.9 2.03 29.3 7.80.9206 128.2 136.5 11.0 4 25.2 CHMMS 15 200 2.0 120 285 11.3 0.11 23.59.6 0.9188 124.6 120.7 10.2 5 25.7 2E2B-DMP 15 200 2.0 120 240 9.3 <0.038.2 0.9192 124.5 123.1 10.42M2O-DMP = 2-Methyl-2-Octyl-1,3-diMethoxyPropane2E2B-DMP = 2-Ethyl-2-n-Butyl-1,3-diMethoxyPropaneCHMMS = cyclohexylmethyldimethoxysilane

TABLE 3 Ethylene/Propylene Polymerization Ext. Don. Cat P H2 TimeC2⁻Bath C3⁻Bath C2⁻feed C3⁻Feed Polymer Example type mg barg L min. g gg g g 6 — 10.4 16.8 1.75 47 1.9 38.1 50 50 119 7 — 10.7 18.1 2.2 25 30367 50 50 98 8 MODMS 11.5 17.2 1 22 31 409 55 45 174 Comp. 1 MODMS 6.718.0 2.2 33 39 407 45 55 150 9 2M2O-DMP 19.0 17.0 0.5 23 35 411 56 64145 Comp. 2 DCPDMS 12.8 18.1 2.5 52 39 408 50 50 126 Comp. 3 DCPDMS 10.818.0 2.8 25 39 408 50 50 119 10  2M2O-DMP 21.0 16.8 0.5 47 29 417 56 64110 11  2M2O-DMP 27 16.3 0.5 86 20 426 56 64 1262M2O-DMP = 2-Methyl-2-Octyl-1,3-dimethoxypropaneMODMS = methyl-octyl-dimethoxysilaneDCPDMS = dicyclopentyldimethoxysilane

TABLE 4 Ethylene/propylene polymers characterization Tensile 2-1 C2Strength at Elong. Max Tens. Max regioinv. IV (NMR) XI Tm ΔH Shore Breakat Break Strength Elong. E100 E200 Example % Mw/Mn dl/g % wt % wt ° C.J/g A MPa % MPa % MPa MPa 6 <1 5.4 2.79 42.0 5.0 116.5 0.6 39 0.3 8251.6 810 0.6 0.6 7 <1 5.1 2.77 53.0 8.5 119.3 1.6 45 1.2 794 1.9 780 0.80.8 8 <1 6.1 2.92 43.3 9.1 115.2 2.1 45 2.7 965 2.7 970 1.1 1.0 Comp. 1<1 5.1 3.20 43.9 13.9 117.6 2.1 55 4.1 931 4.8 924 1.2 1.2 9 <1 5.9 3.3547.3 12.3 119.1 2.6 44 3.1 875 3.2 890 1.1 1.1 Comp. 2 <1 8.7 3.20 45.015.4 120.2 11.3 58 4.3 880 4.4 869 1.3 1.3 Comp. 3 <1 6 3.16 49.0 18.9121.1 13.0 56 3.1 869 3.5 864 1.3 1.3 10  <1 5.8 3.21 58.0 12.0 118.74.9 42 2.3 710 2.3 710 1.0 1.0 11  <1 5.7 3.1 51 8.8 118.1 2.3 36 n.dn.d n.d n.d n.d n.d

TABLE 5 Heterophasic composition characterization C2 IV XI Tm ΔH EXAMPLE% wt dl/g % wt ° C. J/g Shore A Shore D Comp. 3 40.1 2.80 49 166.9 40.088 39 12 40.0 2.31 28 160.2 17.5 56 n.a

TABLE 6 Characterization of crosslinked ethylene/propylene copolymersTensile Strength Elongation C. Set Tension Set at Break at Break E100E200 22 hr/70° C. 200% EXAMPLE Sample MPa % Mpa MPa % % Shore A COMP: 5Comp 2 8.36 340 2.34 4.73 30 28 64 COMP. 6 Comp. 3 8.24 330 2.23 4.51 2930 64 13 Ex. 7 10.98 390 1.95 4.57 21 18 61

1. A process for the preparation of ethylene copolymers comprising thecopolymerization of ethylene with olefins CH₂═CHR, in which R is ahydrocarbyl radical with 1-12 carbon atoms carried out in the presenceof a catalyst comprising the product obtained by contacting (i) a solidcatalyst component comprising Mg, Ti, halogen and a 1,3-diether offormula (I)

in which R is a C₁-C₁₀ hydrocarbon group, R₁ is methyl or ethyl,optionally containing a heteroatom, and R₂ is a C4-C12 linear alkylgroup optionally containing a heteroatom, and (ii) an organo-Alcompound.
 2. The process according to claim 1 in which R is a C1-C5alkyl group, R₁ is methyl and R₂ is a C7-C10 linear alkyl group.
 3. Theprocess according to claim 1 in which the 1,3-diether is2-methyl-2-pentyl-1,3-dimethoxypropane, 2-methyl-2-n-hexyl-1,3-dimethoxypropane, 2-n-heptyl-2-methyl-1,3-dimethoxypropane,2-n-octyl-2-methyl-1,3-dimethoxypropane, 2-n-decyl-2-methyl-1,3-dimethoxypropane, 2-ethyl-2-butyl-1,3-dimethoxypropane,2-ethyl-2-pentyl-1,3 -dimethoxypropane,2-ethyl-2-n-hexyl-1,3-dimethoxypropane,2-n-heptyl-2-ethyl-1,3-dimethoxypropane,2-n-octyl-2-ethyl-1,3-dimethoxypropane, or2-n-decyl-2-ethyl-1,3-dimethoxypropane.
 4. The process according toclaim 1 in which the solid catalyst component (i) comprises a titaniumcompound containing at least one Ti-halogen bond, and an internalelectron-donor compound of formula (I) supported on magnesium halide. 5.The process according to claim 4 in which Mg-halide is in active formand the titanium compound is a titanium halide or a titanium compound offormula TiX_(n)(OR⁴)_(4-n), where 0≦n≦3, X is halogen, and R⁴ is aC₁-C10 hydrocarbon group.
 6. The process according to claim 5 in whichthe titanium compound is selected from titanium tetrachloride and TiCl₃OR, where R is a C₁-C₁₀ hydrocarbon radical.
 7. A solid catalystcomponent comprising Mg, Ti, halogen and a 1,3-diether of formula (I):

in which R is a C₁-C₁₀ alkyl group, R₁ is methyl or ethyl, optionallycontaining a heteroatom, and R₂ is a C4-C12 linear alkyl groupoptionally containing a heteroatom with the proviso that when R₁ isethyl, R₂ is higher than C4.
 8. The solid catalyst component accordingto claim 7 in which R is a C1-C5 alkyl group, R₁ is methyl and R2 is aC7-C10 linear alkyl group.
 9. The solid catalyst component according toclaim 7 in which the 1,3-diether is2-methyl-2-pentyl-1,3-dimethoxypropane,2-methyl-2-n-hexyl-1,3-dimethoxypropane, 2-n-heptyl-2-methyl-1,3-dimethoxypropane, 2-n-octyl-2-methyl-1,3 -dimethoxypropane,2-n-decyl-2-methyl-1,3-dimethoxypropane, 2-ethyl-2-pentyl-1,3-dimethoxypropane, 2-ethyl-2-n-hexyl-1,3-dimethoxypropane,2-n-heptyl-2-ethyl-1,3 -dimethoxypropane, 2-n-octyl-2-ethyl-1,3-dimethoxypropane, or 2-n-decyl-2-ethyl-1,3-dimethoxypropane. 10-23.(canceled)